EclipseLink is an object-persistence and object-transformation framework that provides development tools and run-time capabilities which can reduce development and maintenance efforts, and increase enterprise application functionality. An implementation of the Java Persistence API (JPA) framework is provided by Eclipselink, which enables java classes and objects to be stored in data sources, allowing information to be used across sessions. Using EclipseLink, software applications can be built which store persistent object-oriented data in a relational database; and can be used to transform object-oriented data into either relational data or Extensible Markup Language (XML) elements.
In EclipseLink, application defined objects which have been made persistable are referred to as entities. Entities are managed by an entity manager, which enables various operations to be performed on the entities. Entity managers can be created and configured using a persistence unit, which can be defined in a persistence.xml file.